Neuro Eye Burrell Ssom

Front 1

Eye
3 layers outer to inner

Back 1

sclera
choroid
retina

Front 2

Eye
Sclera
(characteristics)

Back 2

tough, white tissue expect anterior-most region (cornea) which is transparent

Front 3

Eye
Choroid layer
(highly _,
includes _ _)

Back 3

highly vascularized
includes ciliary body (a muscle) and iris

Front 4

Eye
Retina
(includes _ _)

Back 4

includes the photoreceptors and the pigmented epithelium

Front 5

Cornea
(function)

Back 5

coarse focus, not adjustable

Front 6

Anterior chamber
(space b/w)

Back 6

space b/w iris & cornea

Front 7

Posterior chamber
(space b/w)

Back 7

space b/w lens & iris

Front 8

Aqueous humor
(function)

Back 8

supplies nutrients to cornea and lens (fills anterior and posterior chambers)

Front 9

Vitreous humor
(function)

Back 9

maintains eye shape
also removes blood and cellular debris from the eye

Front 10

Iris
(function)

Back 10

controls amount of light that enters the eye

Front 11

Lens
(function)

Back 11

fine focus
adjustable

Front 12

Retina
(function)

Back 12

actual site of photoreception and transmission to brain

Front 13

Pigmented epithelium
(function)

Back 13

absorbs light, thereby increasing acuity
supplies nutrients to & removes debris from the retinal layer

Front 14

Glaucoma
(caused by, results in)

Back 14

caused by increase in pressure in anterior and posterior chambers due to accumulation of aqueous humor in these two chambers
any swelling is then transmitted to vitreous body
resulting in increase in pressure throughout eye
this reduces blood supply to eye, causing damage to retina

Front 15

in the center of the retina is a region called _

Back 15

macula lutea

Front 16

in the center of the macula is a depression called the _

Back 16

fovea

Front 17

fovea
(depression due to, region of _, thinning of the layers does what, also absence of _)

Back 17

due to thinning of layers of eye that are over this part of the retina
region of highest visual acuity in retina due to exclusive presence of cones in the region
thinning of the retinal layers minimizes the distortion of light before it reaches the photoreceptors
also absence of blood vessels around the fovea for same reason

Front 18

macula lutea

Back 18

region in center of retina

Front 19

macula/fovea specialized for _ vision, while regions outside the macula are responsible for _ vision

Back 19

central

peripheral

Front 20

pale, circular region next to macula

Back 20

optic disc

Front 21

optic disc
(opening in eye through which _ enter and _ exit to form _,
no _ in this region resulting in _)

Back 21

blood vessels enter eye
axons from retinal ganglion cells exit
to form optic nerve
no photoreceptors = blind spot in visual field

Front 22

Papilledema
(what, indicative of, causes)

Back 22

swelling of the optic disc
indicative of swelling in the brain due to trauma, infection, or tumor
swelling due to these causes will cause increase in intracranial pressure that will be transmitted throughout CSF, which includes the junction where optic nerve enters the eye

Front 23

Macular Degeneration
(loss of _, what compromised)

Back 23

involves loss of photoreceptor cells in retina limited to macula
central-vision dependent tasks compromised, peripheral unaffected
blurred vision or darkened areas in central vision
total blindness not observed but
reading, driving severely disrupted
distance vision unaffected
2 categories: "dry" and "wet"

Front 24

Focusing apparatus of eye are _ _ _

Back 24

cornea, lens, iris

Front 25

Light that enters eye must be refracted in order to focus image on retina
Refraction carried out by _ but _ responsible for _
It does this by changing shape:
far vision requires _
near vision requires _

Back 25

lens and cornea
lens = fine adjustments in focus

far vision - relatively flat and thin lens

near vision - thicker and rounder lens

Front 26

Lens shape controlled by _ and _

Back 26

ciliary muscles and zonule fibers
(see pg. 5 for how they work)

Front 27

accommodation

Back 27

contraction of ciliary muscles is associated with focusing the lens for near vision

Front 28

Decreases in pupil size _ the level of visual resolution or clarity

Back 28

increase

Front 29

changes in _ also contribute to level of resolution of a visual image

Back 29

pupil size

Front 30

pupil size controlled by _

Back 30

dilation and constriction of iris

Front 31

Cataracts

Back 31

clouding of lens that disrupts the passage of light through the lens resulting in blurring of vision
cataracts occur when the proteins that make up the lens (lens is mostly water and protein fibers) start to degenerate
resulting fragments clump together and form the cataract
untreated, can cause blindness

Front 32

Retina
(part of the eye where _,
damage = ?)

Back 32

where actual sensing of light occurs
part of CNS and damage leads to
permanent loss of vision since these neurons can't regenerate

Front 33

Retinal layers
(name - starting with outermost)

Back 33

pigment epithelium layer
layer of photoreceptor outer segments
external limiting membrane layer
outer nuclear layer
outer plexiform layer
inner nuclear layer
inner plexiform layer
ganglion cell layer
optic nerve layer

Front 34

Retina
Pigment epithelial layer

Back 34

cuboidal cells containing melanin
this black pigment absorbs any light that is not captured by photosensitive cells in the retina, preventing light from reflecting back to retina which would:
(1) lead to degeneration of visual signal on retina
(2) potentially allow damaging levels of light onto the retina photoreceptors

this layer also provides nutritional support to photoreceptors

Front 35

retinal detachment

Back 35

connection b/w pigment epithelium and rest of the retina is not very strong and there is potential for separation = retinal detachment
leads to damage/loss of photoreceptors due to loss of nutritional support

Front 36

layer of photoreceptor outer segments

Back 36

consists of outer segments of the rods and cones

Front 37

external limiting membrane layer

Back 37

simply a membrane that the rods and cones pass through

Front 38

outer nuclear layer

Back 38

contains cell bodies of rods and cones

Front 39

outer plexiform layer

Back 39

contains synaptic connections made by the rods & cones onto the bipolar cells

Front 40

inner nuclear layer

Back 40

contains cell bodies of the bipolar cells

Front 41

inner plexiform layer

Back 41

contains synaptic connections made by the bipolar cells onto the ganglion cells

Front 42

ganglion cell layer

Back 42

contains cell bodies of ganglion cells

Front 43

optic nerve layer

Back 43

contains axons of the ganglion cells on their way to form the optic nerve

Front 44

Retinitis Pigmentosa (RP)

Back 44

inherited visual disorder
characterized by progressive vision loss due to degeneration of photoreceptors
early symptoms: night blindness, reduction of visual field, thinning of retinal blood vessels, formation of clumps of pigment within the retina
pigment is from pigmented epithelial layer disrupted by the disease
night blindness = rods lost first, cones doing all photoreception
as disease progresses, cones also lost = blind
RP really several diseases with similar symptoms

Front 45

photoreception
(what, carried out by)

Back 45

conversion of photostimuli (light) into a neurosignal
rods and cones

Front 46

Cones vs. Rods
sensitivity to light

Back 46

Cones:
low (100 times less sensitive)

Rods:
high (one rod can respond to single photon of light)

Front 47

Cones vs. Rods
Distribution

Back 47

Cones:
high in fovea
very low in rest of retina

Rods:
absent in fovea
high in rest of retina

Front 48

Cones vs. Rods
Color vision

Back 48

Cones:
Yes

Rods:
No (achromatic)

Front 49

Cones vs. Rods
Visual Acuity

Back 49

Cones: high

Rods: low

Front 50

Cones vs. Rods
Relative abundance

Back 50

Cones:
fewer cones than rods

Rods:
20 times more

Front 51

Cones vs. Rods
Specialized for

Back 51

Cones:
day vision

Rods:
night vision (rod responses saturate in daylight)

Front 52

Cones vs. Rods
Effects of damage

Back 52

Cones:
loss of cones = blindness

Rods:
loss causes night-blindness and
loss of peripheral vision

Front 53

Rods are _ to light, but have _ spatial resolution

Back 53

extremely sensitive
low

Front 54

Cones are _ to light, but have _ spatial resolution

Back 54

relatively insensitive to light
high

Front 55

Rods use _ photopigment(s)
Cones use _ photopigment(s)

Back 55

rods - one:
**rhodopsin**

cones - three:
S (short) = violet
M (middle) = green
L (long) = yellow
A single cone uses only one type

(length refers to the wavelength of light that each pigment has the shortest absorbance to)

Front 56

How do we detect so many colors with only 3 photopigments?

Back 56

visual system compares the relative activities of cones with different photopigments to determine what color (what wavelength) the light is

Front 57

Color Blindness

Back 57

caused by lack of cones that are sensitive to a particular color
most common form is red-green (6% of population)
which is due to loss of the middle cone photopigment
green or blue color blindness exist also (blue is uncommon)
red-green blindness is inherited via recessive allele on X-chromosome and is more common in males than females

Front 58

Phototransduction
(how do rods and cones respond to light, the response results in _)

Back 58

*rods and cones do not respond to light by firing action potentials, but instead respond with graded changes in membrane potential

this response to light results in hyperpolarization of rod/cone membrane potential

Front 59

Flow of info thru retina

Back 59

light strikes the rods/cones>
hyperpolarizes rods/cones decreasing neurotransmitter release >
bipolar cells are depolarized increasing their neurotransmitter release >
Ganglion cells are depolarized & action potentials are initiated

Front 60

light adaptation

Back 60

process of adapting to overall levels of illumination (like going from inside to outside)

Front 61

Refractive errors = ametropia
(name)

Back 61

Myopia
Hypermetropia
Emmetropia
Astigmatism
Presbyopia

Front 62

Myopia

Back 62

cannot bring distant objects into focus (nearsighted)
caused by the cornea being too curved or the eyeball being too long

Front 63

Hypermetropia

Back 63

cannot bring near objects into focus (farsighted)
caused by eyeball being too short

Front 64

Emmetropia

Back 64

normal vision

Front 65

Astigmatism

Back 65

either the lens or cornea do not have a uniform curvature, therefore the light rays do not all get focused onto the same point

Front 66

Presbyopia

Back 66

aging leads to decreases in elasticity of lens,
making it increasingly difficult for lens to obtain appropriate curvature when the ciliary muscle contract to focus on near objects
the minimal distance at which we can focus upon near objects gets farther away,
impairing detailed near vision tasks (reading)